title: The interactions of phenylalanines in β-sheet-like structures from molecular orbital calculations using density functional theory (DFT), MP2, and CCSD(T) methods.
abstract: We present density functional theory calculations designed to evaluate the importance of π-stacking interactions to the stability of in-register Phe residues within parallel β-sheets, such as amyloids. We have used a model of a parallel H-bonded tetramer of acetylPheNH2 as a model and both functionals that were specifically designed to incorporate dispersion effects (DFs), as well as, several traditional functionals which have not been so designed. None of the functionals finds a global minimum for the π-stacked conformation, although two of the DFs find this to be a local minimum. The stacked phenyls taken from the optimized geometries calculated for each functional have been evaluated using MP2 and CCSD(T) calculations for comparison. The results suggest that π-stacking does not make an important contribution to the stability of this system and (by implication) to amyloid formation.
authors.affiliation: Department of Chemistry, City University of New York-Hunter College and the Graduate School, 695 Park Avenue, New York, New York 10065, USA.
authors.forename: Gabor
authors.initials: G
authors.lastname: Pohl
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Plumley
authors.forename: J J
authors.initials: JJ
authors.lastname: Dannenberg
mesh_terms: D006860:Hydrogen Bonding; D010455:Peptides / Q000737:chemistry*; D010649:Phenylalanine / Q000737:chemistry*; D017433:Protein Structure, Secondary; D011789:Quantum Theory
chemical_list: D010455:Peptides; D010649:Phenylalanine